Ink ribbon feed and reverse mechanism



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INK RIBBON FEED AND REVERSE MECHANISM Original Filed March 30, 1961 5Sheets-Sheet 2 INVENTOR Hilding A.Anderson BYJM pddgf ATTOR Feb 1, 1966H. A. ANDERSON 3,232,229

INK RIBBON FEED AND REVERSE MECHANISM Original F iled March 30,' 1961 sSheets-Sheet 5 INVENTOR Hilding A. Anderson ATTORNEYS 5 Sheets-Sheet 4Feb. 1, 1966 H. A. ANDERSON INK RIBBON FEED AND REVERSE MECHANISMOriginal Filed March 30, 1961 h x mm l m x9 x m m|-- 4 m O9 09 x? x8 v5V5 E Y B vam I w Eda 4 n n l 2:: ow om, 556mm 8| I $55 n u amma -w+ xmmxmm xmn 51w mzo vw SE zomma m I II moon W v. 29% MN I T V5; c9 09 ivflfi m m wfi 2891 ON] 556% ON] United States Patent 3,232,229 INK RKBBUNFEED AND REVERSE MECHANISM Hilding A. Anderson, Lake Zurich, Ill.,assignor to SCM gorporation, New York, N.Y., a corporation of New orkOriginal application Mar. 30, 1961, Ser. No. 103,183, new Patent No.3,131,627. Divided and this application Apr. 23, 1964, Ser. No. 362,047

2 Claims. (Cl. 101-336) This invention relates to an ink ribbon feed andreverse mechanism and its control equipment and is particularly relatedto use of such ink ribbon equipment in combination with a high speedprinting apparatus designed to print a message, coded or otherwise, on apaper tape, said message being received as electrical code signals whichoriginate in a telegraphic or data processing system or other similartelegraphic mediums. This application is a division of co-pending US.application Serial No. 103,183, filed March 30, 1961, now Patent No.3,131,627 for High Speed Serial Printer.

The invention in the aforenoted parent application uses, as a basicprinciple of operation, electronic selection and actuation of a printhammer which is aligned to print a serial message on a tape from a rowof characters positioned around the periphery of a continuously rotatingtypewheel. In recent years, as the need for higher speed printers hasbecome urgent, printing on the fly or printing without stopping therotation of the typewheel has come into prominence, particularly inconnection with printing computor output information delivered at highoutput rates. The present invention is herein disclosed in combinationwith an exemplary high speed printer utilizing an electromagneticimpulse transducer form of typewheel position detector where a pulse isgenerated for each typewheel position starting from an indexing point(or points) and the pulse counts compared with an incoming code signalin an electronic counter to determine the typewheel position. Printhammer actuation is then controlled relative to instantaneous shaftposition to record any desired character while the typewheel isrotating. The required shaft position impulses may be obtained in otherknown Ways such as by photocells with a perforated clock disc and alight source. The control mode of the ink ribbon feed mechanism, of thepresent invention, in other Words, stepping of the feed mechanism byelectronic control which by means of electronic circuitry reduces therate of ink ribbon teed steps relative to machine rate of operation,could also be applicable to relatively low speed printers where shaftposition impulses can be obtained by brushes and commutators, althoughthe advantages of the invention are primarily realized in combinationwith high speed printers.

Very briefly, the tape printer in which the present invention isdisclosed uses two rows of type characters, each type row having itsassociated print hammer, a dual tape stepping mechanism which isassociated, through control apparatus, for specific ditierent modes ofoperation with each specific print hammer and an ink ribbon which feedsbetween the tape and a print wheel. Whichever row of characters includesthe character selected for printing, printing will occur at the nextserial print position on the tape. This is accomplished by utilizing twobasic modes of machine operation, termed PRINT FIRST- THEN SPACE (forcharacters in typewheel row #1) and SPACE FIRSTTHEN PRiNT (forcharacters in typewheel row #2). The appropriate mode of operation isautomatically determined by the machine upon receipt of the appropriatecharacter signal (the signal being coded according to desired typewheelrow). Two additional modes of operation, essentially functional, arealso pro- 3,232,229 Patented Feb. 1, I966 ice vided: a SPACE-NO PRINTmode and a MANUAL TAPE FEED-OUT mode. For convenience in circuitry, inkribbon feed is actuated electronically during all modes of operation butits rate is only one-half that of code signal reception by the printer.

Accordingly, a principal object of this invention resides in theprovision of a novel, electronically controlled and powered ink ribbondrive mechanism in an electromechanical tape printer capable ofoperating at very high speeds.

Another object resides in the provision of a typewheel serial printerhaving a complete ink ribbon feeding and reversing mechanism with anovel electronic control and power circuit correlated with printeroperation and reducing the rate of drive of the ink ribbon mechanismrelative to that of printing and spacing operations, thus effectivelyreducing ink ribbon wear and increasing the speed and efficiency ofprinter operation.

A further object resides in providing in combination with a high-speedelectronic serial printing tape printer with stepping tape feedmechanism, a novel electronic ribbon feed control correlated with theelectronic print and space control.

Further objects and advantages of the invention will be apparent fromthe following description and the appended claims taken in conjunctionwith the accompanying drawings showing a preferred embodiment thereof,in which:

FIGURE 1 is a block diagram of a printer with electronic controls and anelectronically controlled ribbon feed and reverse mechanism in accordwith the present invention, the electronic control and mechanicalcomponents being illustrated by schematic symbols;

FIGURE 2 is a fragmentary perspective View of a printer, in whichsupport structure and control circuitry are deleted, illustrating theprimary mechanical components, the typewheel shaft position detectorclocks with transducer members and the solenoids which operate themechanical print hammer, tape feed and ribbon feed components;

FIGURE 3 is an enlarged top plan view of the mechanical components ofthe ink ribbon feed and reverse apparatus;

FIGURE 4 is a perspective view of the ink ribbon feed and reverseapparatus seen in FIGURE 3;

FIGURE 5 is a detailed partially sectioned view of the right-handmechanism of the ink ribbon feed and reverse apparatus of FIGURE 3; and

FIGURES 6 and 7 taken as a unit will provide a detailed circuit diagramof an exemplary transistorized printer circuit for control of the inkribbon drive in accord with the present invention. The detailedcomponents of this circuit diagram correspond to portions of thesymbolized schematic diagram of the electronic components in FIGURE 1pertaining to the ink ribbon controls, and representative symbolizedcomponents are included with the individual FIGURES 6A and 7A assubscript figures of FIGURES 6 and 7 to enable a rapid correlation ofthat portion of the detailed circuit with the overall symbolized circuitof FIGURE 1. For example, FIGURE 6A is the symbol for the ribbon feedone-shot, current driver and solenoid circuits detailed in FIGURE 6 andFIGURE 7A is the symbol for the detailed ribbon feed divide-by-twocircuit shown in FIGURE 7.

The following description is of a specific electronic high speed printerutilizing the ink ribbon control and power circuitry for feed drive inaccordance with the present invention. It is to be understood that theinvention is not restricted to be exemplary transistorized circuitcomponents illustrated in FIGURES 1, 6 and 7. Other types of circuitcomponents and devices may be employed in the ink ribbon control anddriving circuit, for example, vacuum tube switching circuits may beused. The illus- 3 trated transistorized circuit, however, doesrepresent an operative and preferred construction.

The complete circuit combination and some subcombination circuits arenovel and are fully described in the aforenoted parent application, nowPatent No. 3,131,627. Inasmuch as the various components of the detailedcircuit of FIGURES 6 and 7, such as the and gates, delays, one-shots,current drivers, counters, registers, etc., are known, they will not bedescribed in detail except for the following aspects. These orequivalent circuits, of course, could utilize electron tubes, but toconserve space, power, avoid heat and obtain long life of operatingcomponents, the transistorized circuits are preferable. All of thedepicted transistors in FIGURES 6 and 7 are 2N1372 unless otherwiseindicated on the figures. All diodes are Germanium D1034 unlessotherwise marked. Silicon diodes are marked S1 and are SR162 unlessotherwise indicated. All resistor values are noted in ohms and are Awatt unless marked otherwise. All capacity values are in ,uaf. unlessmarked otherwise.

GENERAL DESCRIPTION By preliminarily stressing several basic aspects ofthe printer operation, and keeping these aspects in mind, the detaileddescription which follows will be more clearly understood.

Referring for a moment to FIGURE 2, the general arrangement of themechanical components of the printer can be seen. The drive motor 26 ispreferably mounted on the base structure but for convenience ofillustration is shown moved to an upper location. The printer has a dualrow typewheel 22 which, during printer operation, is constantlyrotating, being secured on a shaft 24 which is suitably journalled inthe frame of the machine (not shown) and is driven by a synchronousmotor 26 through pulleys 28 and 29 and a pulley belt 30. Also secured torotate with shaft 12 is a two (2) notched clock wheel 32 and asixty-four (64) notched clock wheel 34. The two notches 35 and 36 onclock wheel 32 are indexing points at the beginning-of-count position onthe typewheel 22 while the sixty-four (64) notches 37 on clock wheel 35are aligned with respect to the sixty-four character positions aroundthe typewheel 22.

Clock wheels 32 and 34 are metallic discs made of high permeabilitymagnetic material (such as wrought iron or mild steel), the notches ineach, as the edges of the discs pass close to the magnetic pick-upmembers, causing a change in flux density in the magnetic field aroundthe index coil 38 and impulse counting coil 39 of the pick-up members.This change in flux density induces a surge of current and a changing inthe pick-up circuits. The voltage signal is amplified and shaped byrespective amplifiers 41 and 43 (FIGURE 1) which feed the indexing andcounting signals to the machine control circuits, to be hereinafterdescribed. Clock wheels 32 and 34 must not become permanentlymagnetized, otherwise the machine will not work.

The machine is a serial tape printer, it prints one character or symbolor causes a space function of a message one unit at a time in a singleline on a tape, the character to be printed being chosen from one or theother of the inner row 42 or the outer row 44 of the dual row typewheel22. In the preferred embodiment, the characters in one row are differentfrom the characters in the other row. Thirty-two different printcharacters or symbols can be included in each row and are repeated at180 intervals in the same row.

Still referring to FIGURE 2, a paper tape feeds from right to left froma supply roll (not shown) by mechanism described in detail in theaforesaid parent and in a co-pending divisional application. To aid inunderstanding, the inner typewheel row 42 is on the incoming tape sideand the outer typewheel row 44 is on the tape feed-out side.

To serially print a message on the tape in this machine withoutoverprinting and in order to operate the machine in a useful manner, themachine is capable of four basic modes of operation, now brieflydescribed, and referred to throughout the following description.

(1) If the character to be printed is located on the inner typewheelrow, the machine will print-first and then space the tape. This will bereferred to as the PRINT- SPACE" mode of operation. Note, at the end ofthis operation the tape is properly positioned to undergo a succeedingPRINT-SPACE operation if the next character to be printed is located onthe inner row.

Although the tape has been stepped so that the character just printed isnow directly under the outer typewheel row, a character selection fromthat row will not overprint because of the next described mode ofoperation.

(2) If the character to be printed is located on the outer typewheelrow, the machine will space the tape first and then print the character.This will be referred to as the SPACE-PRINT mode of operation. Note, atthe end of this mode of operation the tape is positioned with the justprinted character under the outer typewheel row, the same .as the finishposition of the PRINT-SFACE mode of operation. Thus the machine is readyto undergo a succeeding mode of operation which can be eitherPRINT-SPACE or SPACE-PRINT depending upon which row contains thecharacter to be printed. In this manner, the resultant printed messagewill be properly serially recorded on the tape.

Determination of one or the other of the above two ibriefiy describedmodes is by a sixth bit added to a five unit code signal combination,which in fact makes the code signal a six bit combination. Dependingupon the presence or absence of a positive sixth bit pulse in thereceived signal, the control circuitry, which will be fully described,selects the mode of operation to record the desired character from theproper row.

Another point to be understood is that there are two print hammers, oneof which is used only with the inner typewheel row of characters and theother of which is used only with the outer typewheel row of characters.

(*3) A third mode of operation is designated the space but no printingmode, i.e., SPACE-NO PRINT. Thus, if a space code signal is received,there is an automatic inhibiting of the operation of the counting andprinting control circuits as a result of which, no printing actuationoccurs. Yet at this time, a space signal is immediately directed to thetape feed mechanism, resulting in a spacing of the tape but no printing.

(4) The fourth mode, entitled MANUAL TAPE FEED, is just what its nameimplies. This operation is provided by a switch which inhibits counterand printer operations and feeds signals directly to the tape feedmechanism.

As previously mentioned, to hurdle the mechanical speed limitations oftape feed mechanisms, duplicate tape feed devices are provided and theiroperation is alway successively alternate. This is true regardless ofwhich one of the four modes of operation is utilized.

The ink ribbon feed for the typewheel ink ribbon is stepped once forevery second printer cycle of operation. The circuitry for thisoperation is electronic and will be described.

The printer operates from six lines of data, received in parallel, plusa strobe line. As is conventional, each line furnishes one of twosignals, sometimes referred to as yes-no, mark-space or pulse-no pulse.Information can be accepted at the rate of from 0 to 30 characters persecond.

For convenience, the exemplary printer has been arranged to receive codesignals in the form of five-unit binary code combinations. The source ofthe signals is not a part of the present invention; it may be atelegraphic transmitter, the output from a data computor or a datastorage device such as a magnetized tape record. Merely by way ofexample, it signals are derived from a tape storage device, the binarysignals recorded on the magnetic tape induce pulsating voltages in thepick-up head, which voltage signals can be amplified and/ or shaped asdesired and applied through corresponding leads to a five stage binarycounter circuit (see top of FIGURE 1) of the printer of this invention.The code combination jams or pre-sets the counter to a desired countcondition. Also, a sixth bit signal line leads to the sin le stagebinary counter No. 6 (also at the top of FIGURE 1) which determines theselection of operation modes 1 and 2 (PRINT-SPACE or SPACE-PRINT), and aseventh input signal line to the strobe input (No. '7 at bottom left ofFIGURE 1).

The position detection pulse generated counts correspond to five unitbinary code numbers. Many arrangements of the order of charactersrepresented by serially generated binary code combinations are, ofcourse, possible. For example, the 180 out-of-phase positions 1 and 33on the typewheel and on the sixty-four notch clock disc could both befor the two characters A and B, and the serial pulse count of one fromthe sixty-four notch wheel as expressed by the five unit binary codewould be 00001. The binary code 00001 represents both characters, butthe characters are on different rows, e.g., A would be on the inner rowof the typewheel and B on the outer row of the typewheel. Similarly, Cand D could be represented by a two count pulse, which is the five unitbinary code 00011, E and F by the three count pulse or code 00100 and soon for thirty-two sets of two or a total of sixty-four differentcharacters (symbols, numbers, etc.).

Returning to the binary counter, as has been stated, it is thedestructive read-out type, i.e., the counter is preset by the receivedsimultaneous code signal and pulses sent into the counter by thesixty-four (64) notch clock wheel 34 will complete the counter operationfrom the pre-set count, through the thirty-two count whereupon thecounter returns to its zero count condition, at the same time providinga control pulse signal to operate the printer functions.

In destructive read-out, the code combinations repre senting characterson the incoming signal lines are the complement of the serially producedbinary signal count from the printer clock disc. Thus, using the fiveunit binary code (thirty-two numbers not including zero), thecomplementary number for the A and B print positions, noted previouslyas being 00001 in the printer, wouldibe 31 or 11111.

To print A or B, therefore, the incoming code signal on lines 105 wouldconsist of a pulse on each line or 11111 which will jam or preset thebinary counter to 31'. Thus when one (1) pulse is received from thesixty-four notch clock disc (after an index pulse) one or the other ofthe two characters A and B can be printed. With A located on the innerrow 42 of the typewheel 22 and B on the outer row 44, the absence orpresence of a signal pulse on the sixth incoming line will be used todetermine whether the desired character to be printed is A or B.

CONTROL CIRCUIT AND OPERATION Inasmuch as the mechanical printercomponents are actuated and, in fact, powered by the control circuit,the control circuit will be first described, leaving the specificdetails of pertinent mechanical components of the printer and the inkribbon mechanism to be described in detail in a later portion of thisspecification.

In describing the control circuitry, reference will be primarily toFIGURE 1 and the symbolized components such as the binary counterregisters, and units, delay units, current drivers, etc. The specificmanner in which each circuit component accomplishes its function will beunderstood by those skilled in the art and relative to the ink ribboncontrol and power circuitry is clearly apparent from the detail circuitsin FIGURES 6 and 7.

As has been forenoted, the printer has four modes of operation,PRINT-SPACE, SPACE-PRINT, SPACE-NO PRINT and MANUAL FEED-OUT. Thecircuits to accomplish these modes will be described in the order named.

PRINT-SPACE MODE The print-space mode records a character on the innerrow of the typewheel 22 and then feeds the tape 40 one step. Because theadjacent two difierent characters on the typewheel inner and outer rows42 and 44- are represented by a single incoming simultaneous five unitbinary code to binary counter 50 and are also represented by a singleserial binary count (complement of the simultaneous code) from the clockdisc 34, one additional incoming data line 6 is used to determinewhether there will be a print first-space later operation or a spacefirst-print later operation. If no information is received from dataline 6 by the sixth register 46, the character desired for selectionwill be on the inside row at of typewheel 22, and accordingly, thecharacter must be printed first and the tape 40 must then be stepped. Inthe print first-space later condition, binary code information isreceived on lines #1 through #5 to the binary counter registers 5l55 andno signal will be present on line #6 to register 46. At the same instanta strobe signal will be received on line '7 which is connected to a 150microsecond relay 56 to assure that the received data on lines l-S iscompletely entered in the registers 51 through 555 of counter 50.

From the 150 microsecond delay 56, the strobe signal pulse passesthrough a circuit line 57 to several branches, one of which is a ribbonfeed divide-by-two register which requires two consecutive pulses to0pcrate a ribbon feed one-shot multivibrator 60 of 14 1nilli secondsduration which in turn feeds a current driving stage 62 to activate aribbon feed solenoid 64 to move the inking ribbon 66 (see FIGURES 2, 3and 4). Thus the ink ribbon feed mechanism will be activated once forevery other strobe input signal.

The 150 as. delayed strobe pulse on line 57 is also presented to aspace-no print blocking gate 68 which, as will be later described, isblocked only when a simultaneous 00000 condition is present in binarycounter 50. So long as a character signal is present on input lines 1-5,the blocking gate 63 passes the delayed strobe pulse to an A register70, cocking the A register 70 to enable acceptance of indexing signalinformation from the amplifier 4.1 of the two notched index wheel 22 onthe typewheel shaft 24. Cooking of register A pulses a 14 ms. delayone-shot 72 which is tripped to provide a 14 ms. blocking of a resetline 76 to a B register 74, by means of an end-of-count and gate 75.

The first index pulse from the pick-up coil 38 of the two notch Wheel 32passes through its amplifier stage 41 to the reset line of the Aregister 70 which trips and, in turn, trips the B register 74. Trippingof B register 74 through a circuit line 78 opens the and gate 79 to thebinary counter input line 80, permitting the sixty four (64) notch clockdisc 34 to serially enter its pulse through its amplifier stage 43 andthe opened an gate 79 into the 2 counter stages of binary counter 50.The serial pulses entered into the 2 counter registers 5155 complete thecount, previously pre-set by the received simultaneous binary code dataon lines 15, to zero. The final serial pulse from clock wheel 34, whichclears the binary counter 50, gives rise to an output of the fifth stage55 which feeds back through previously described reset line 76 to andthrough the end of-count and gate 75 to turn off the B register 74which, in turn, closes the count and gate '79.

If an end-of-count signal on the reset line 76 from binary counter 50occurs before the 1.4 millisecond delay 72 (which controls theend-of-count gate 75) has completed its time cycle, theend-of-count-gate 75 remains closed and the B register 74 will not beturned off. Accordingly, the sixty-four (64) notch wheel 34 and pickup39 will continue to dump pulses through the counter input gate 79 intothe 2 counter registers 51 through 55 (which at this stage of the cycleare not longer pre-set) for thirty-two more pulses (186 rotation oftypewheel shaft taking 15.2 ms.) and the ensuing end-of-count pulsethrough line '76 to the now open end-of-count gate will reset the Bregister 74, closing the count gate 79.

When the B register becomes reset, a signal goes out on a circuit line81 to a 500 microsecond delay one-shot 82 and prevents the #6 register46 from being prematurely reset. This same signal from B register 74 online 81 also goes to three additional units, (1) a paper feed and gate85, (2) a print hammer and gate 83 which controls an actuating signal tothe print-space (PS) print hammer actuation circuit, and (3) a secondprint hammer and gate 8 2- which controls an actuating signal to thespace-print (SP) print hammer circuit.

In the presently considered print first-space later (PS) condition, thePS print gate 83 has been initially conditioned by the fact that therewas no data input on the input line 6 to register 46 and, therefore,when the pulse from B register feeds to the PS print gate 83, the signalpasses to a phasing one-shot delay 86 which in turn pulses a one-shotmulti-vibrator 87 and a current driven stage 83, which in turn energizesa PS hammer operating solenoid 89. When PS solenoid 89 is energized, thecorresponding print hammer 90 (see FIGURE 2a) is caused to record theselected character from the inner type- Wheel row 42 on the tape 40.

Because in this PS mode of operation no data was received on the receivesignal line 6 to register 46, the aforedescribed paper feed and gate 35was conditioned at the same time as was the PS and gate 83 so that whenthe pulse comes from B register 74, the signal passes through the feedand gate 35 and a pulse is sent to a paper feed divide-by-two register94 which in turn pulses one of two paper feed one-shots 98 or 100 totrigger a corresponding one of two current drivers 101 or M2, whichenergizes an associated one of two feed operating solenoids 103 or 164.Successive pulses to the paper feed divide-by-two register 94 operatealternate ones of the two paper feed solenoids 103 and 104.

SPACE-PRINT OPERATION Considering now the second mode of operation, ifthe character to be printed is located on the outside row 44 oftypewheel 22, a space first-print later (SP) operation is required. Inthis instance, data information will be received on the input line 6 toregister 46 coincident with the received binary code data on lines 1-5.A signal data pulse on line 6 resets register 45 and sends currentthrough circuit line 108, a branch of which feeds the current to drive a5 millisecond delay 110. After the 5 millisecond delay, a pulse from thedelay unit through a circuit line 111 by-passes paper feed and" gate 85and will directly enregize the paper feed divide-by-two register 94 toalternately drive one of the paper feed oneshots 98 or 101 theassociated one of the current drivers 101 or 162 and finally theassociated one of the two teed solenoids 163 or 1M. The paper tape 40 isthus stepped after only a 5 millisecond delay without waiting for anoutput pulse on line 81 from the B register '74.

The #6 register 46 also determines which of the two hammers, the insidePS hammer 90 or outside SP hammer 112, is to be used for printing. Inthis instance, SP mode of operation, the output from the 0 side ofregister 46, which is now in reset condition, will condition the SPprint hammer gate 84 so that when an output pulse from B register 74 isreceived on line 81, the SP print hammer gate 84 is open and will feed apulse to the SP phasing one-shot delay 114, thence on to the SP one- 8shot multivibrator 116 and finally t0 the current driving stage 118,energizing SP print hammer solenoid 119 to actuate the SP print hammer112.

The output pulse from B register 74, as has been described in the PSmode, also pulses the 500 microsecond delay one-shot 82 which clears the#6 register 46 to its set condition and relieves the SP controls throughline 1 33 on the paper feed gate and the SP print hammer circuits.

SPACE-NO PRINT O'PERATION Considering now the third mode of operation,the signal operated tape feed-out function (space-no print), no data isentered into the 2 binary counter 50 nor through the #6 line to register46 (i.e., the binary code s gnal 00000 and a sixth 0). However, thestrobe pulses to strobe line 7 will be continuously sequentiallyreceived. 0 condition circuits between binary counter 50 and thespace-no print and gate 67 provide for the 0 condition of all ofregisters 51-55 to open the space-no print control gate 67, which inturn conditions the previously described space-no print blocking gate 68to closed condition. When gate 68 is closed, it prevents the delayedstrobe pulses on strobe input delay line 57 from passing through to theA register 70 and this in turn inhibits the count triggering function ofthe index pulses from the two notch wheel Nevertheless, the delayedstrobe pulse in line 57 is channeled to both the ribbon feed mechanismdivide-by-two register 58 and through an and gate 120, which isconditioned by the 60000 controlled pulse in circuit line 57 from thespace-no print control gate 67, to the aforedescribed 5 milliseconddelay 11%. From delay 11% the pulse is fed through line 111 to thedivide-by-two paper feed register 94 and alternately through delays 98or and current drivers 191 or 102 to the associated fccd solenoid 193 or164.

Thus, one or the other of tape feed solenoids 103 and 104 is energizedto step the paper tape 48 one step for each strobe pulse received online 7 and this stepping occurs without actuation of the print selectingmechanism which is completely inhibited so no printing of characters andno counting of pulses occurs.

MANUAL TAPE FEED-OUT OPERATION In the fourth mode of operation, manualtape feed-out, a manual switch button 122 (bottom center of FIGURE 1) isclosed to ground. While the printer motor is running, closing of switch122 will condition a manual ribbon and feed control and gate 124,permitting the ampiified indexing pulses from the two notch wheel 32 topass through the gate 124 to the aforedescribed ribbon feeddivide-by-two register 58, and thence on to the ribbon feed circuit. Thepulses in this circuit branch off through a manual feed and gate 126 tothe divide-by-two paper iced register 94 and thence through theaforedescribed paper feed circuit to step drive the paper feedmechanism.

The ribbon feed mechanism is operated at this time (as well as in allother modes of operation) even though no printing takes place and suchfeed is permitted due to the fact that it simplifies the electroniccircuitry.

The SP mode of operation up through the pulsing of the 500 s. delay 82will be completed in from 15 to 29.85 ms. The strobe pulses and receivedsignal groups are received every 33 ms. or 30 times each second whichwill permit at least a 3 ms. period between each character countingcycle.

MECHANICAL STRUCTURE AND OPERATION Referring primarily to FIGURE 2, therelationship between all mechanical components can be seen. The motor26, pulleys 2%, 29, belt 38, typewheel and clock disc shaft 24 typewheel22, the two (2) notch indexing clock disc 32, and the sixty-four (64)notch position pulse clock disc 34 have been described.

Tape feed.The dual tape feed mechanism, the two independent drivingassemblies which operate alternately in response to successive operatingcycles of the machine is fully described in the aforenoted parentapplication and is disclosed and described in a co-pending divisionalapplication Serial No. 362,046.

Printing mecha'nism.The print hammer mechanism 1% is shown incombination with the other mechanical components in FIGURE 2 and isherein described primarily because of its relationship to the inkribbon. The FS and SP print hammer solenoids 8? and 11), previouslydescribed in conjunction with the control circuit, are energized, inresponse to receipt of a character code and a signal determining whichof the two solenoids is to be enregized, in timed relation to theretation of characters on the rim of the typewheel so a print hammerwill impact the proper character in its pass above the printing station.

As previously described, two distinct print hammers 90 and 112 areprovided, hammer 90 being associated with the PS solenoid 89 and used toprint characters carried by the typewheel inner row 42, and hammer 112being associated with the SP solenoid 119 and used to print characterscarried by the typewheel outer row 44. The two hammers 9i! and 112 areclearly seen in FIGURE 2 arranged in tandem along the tape feed path andadjacent the bottom center of the typewheel 22. Each hammer has a lowmass and consists of a fiat bar-shaped shank and a small impact head,the shanks being reciprocally guided in a slotted bracket device (notshown) secured to the machine base. Movement of each hammer is in astraight vertical path radially with respect to the typewheel. One edgeof each hammer shank is notched to receive an end of an associatedsolenoid armature lever 200, 2%. A hammer return spring 202 and 264 isfastened to the lower end of each hammer shank, the other ends of thesprings being fastened to a spring anchor bracket 2% which is fixed tothe machine support structure. The hammer heads, in retracted position,will be disposed in recessed cavities in the upper surface of a tapeguide plate. Armature levers 280 and 2&1 extend side by side toward thetwo print hammer electromagnets t3) and 119 and are pivoted on ahorizontal rod mounted in cars of the bridges and of the electromagnets.

In the printing operation, if the PS magnet coil 89 (for example) isenergized by the control circuit, the pole end of armature 260 is pulledtoward the electromagnet, pivoting on its support rod. The opposite endof armature 2% moves up sharply to vertically shift the PS hammer 99causing its head 194 to strike the underside of tape 44 forcing itagainst the ink ribbon 130 and the ink ribbon against the appropriateprint character on the inside typewheel row 42 to cause an inked imprinton the tape. Energization of electromagnet 39 is a one-shot of minuteduration, the coil being de-energized before the hammer impact occurs.Accordingly, the hammer and armature retract springs, upon impactrebound, cause immediate return of the hammer 90 to its rest position.

Mechanical actuation of the SP hammer 112 is identical to that of hammer9h excepting its head impacts the tape and ink ribbon against theselected character on the outer typewheel row.

Ink ribbon meclzanism.-This mechanism includes ink ribbon feed andautomatic direction reversal when a reel is fully unwound and will bedescribed with specific reference to FIGURES 3, 4 and 5 and generalreference to FIGURE 2.

In this mechanism as in the tape feed and the printing mechanism,operation control and power resides in the aforedescribed electronicprinter circuit, a ribbon movement or shift being accomplished each timean impulse signal causes momentary energization of the ribbon feedsolenoid 64.

The mechanical components of the ink ribbon mechanism are mounted on avertical plate-like bracket 232 10 (FIGURE 4) which is secured to themachine base plate. The bracket has been omitted from FIGURE 2 forpurposes of clarity.

A small bent shelf 234 extends forwardly from the approximate mid-pointof the lower edge of bracket 232 and mounts the ribbon feed solenoid 6%.This solenoid 64 faces the vertical plate bracket 232 and its plunger236 shifts fore and aft in a horizontal path, being biased in an aftdirection toward the bracket 23.2 by an encircling coil spring 233. Alink 24% in approximate alignment with plunger 236 is pivotally fastenedat one end to the rear end of plunger 236 and has its other endpivotally connected by a common pivot to one end of a guide link 2 52and one end of an operating link 244. Guide link 24?; has its other endpivotally fastened to a fixed lug 246 While the other end of theoperating link 244 is pivotally fastened to the approximate mid-point ofa pawl lever 248. The rearward end of pawl lever 248 is pivoted to afixed lug 259 and its forward end pivotally carries a pawl 252 which isbiased by a pawl spring 254 into engagement with a ratchet wheel 256non-rotatably fastened on a ribbon reel drive shaft 258.

As is clearly apparent from FIGURE 3, the reel drive shaft 258 carriesother components, to be described hereinafter, and each of its endsjournalled in one of a pair of spaced ears of a U-shaped bracket 266rigidly secured on the support bracket plate 232. The mounting of shaft258 in bracket 269 permits a slight axial shift for ribbon feed reversalpurposes, as will be described. Returning to FIGURE 4, the dispositionof links 246, 242, 244 and lever 248 is such that a forward shift of thesolenoid plunger 236, when solenoid 64 is energized, will tend tovertically align the guide link 1242 and operating link 244, whichforces the pawl lever 248 to shift clockwise. This movement of lever 2%will shift pawl 252 to engage a tooth of and rotate the ratchet wheel256 and shaft 258 one step clockwise. A spring loaded detent 262 (behindthe ratchet wheel) engages the ratchet to prevent reverse movement ofthe shaft 258 when the pawl retracts back over the ratchet teeth.

Retracting force is derived from stored energy in coil spring 238, theretract limit stop position being determined by abut-ment of thecombined pivot connection of links 24%, 242 and 244 with the end of anadjustment screw 264 threaded in the bracket plate 232.

Two parallel and horizontally arranged ink ribbon spindles 270 and 272are journalled on the front side of the support bracket plate 232 andextend adjacent the ends of the ribbon operating shaft 258. Large gears278 and 280 are attached to respective ribbon spindles 27d and 272 andink ribbon reels 282 and 284 slip over the spindle ends 286 and 288 anddrive connect to the spindles by means of the fingers 2%. The reels arelocked in place by the swivel lock tabs 292. As shown in FIGURE 2, theink ribbon 23% passes from the inner side of one reel up and over thetape guide plate, over the hammers 9i and 112 and over the tape 4t). Asuitable ribbon guide device (not shown) is preferably fastened on thetape guide plate 210 to maintain the ink ribbon 236 in its lateral pathdirectly under the typewheel 22.

Referring now to FIGURE 3, it will be seen that two small gear units 274and 276 with axial sleeves 294 and 296, having radial flanges 298 and 303 spaced from the gear portions 274 and 276, are non-ro-tatably fixed onthe ribbon driving shaft 258. Note the sleeves are also non-rotatablyand axially secured on shaft 258 and will be described further inconnection with ribbon feed reversal. In FIGURE 3, the right-hand smallgear 274 is meshed with the righ-hand ribbon spindle gear 278 while theleft-hand small gear 276 is not in mesh with its spindle gear 2%. Aslight leftward axial shift of the drive shaft 258 will disengage theright-hand gears 2.74 and 278 and engage the lefthand gears 276 and 28%,this function being a part of ribbon reverse. But for the present, it isnoted that with gears 274 and 278 in mesh, stepped rotation of 1 1ratchet wheel 256 clockwise (FIGURE 4) will rotate the right ribbon reel282 counterclockwise to wind ribbon 23th on reel 282 and remove ribbonfrom the lefthand reel 284. When gears 276 and 280 are meshed,obviously, the winding operation between reels is reversed with reel 284being the take-up reel.

With respect now to the automatic reversal mechanism, each of the smallgear unit sleeves 294 and 2% non-rotatably carries a gear worm and 384respectively between the associated small gear 274 or 276 and associatedradial flange 2% or 3%. Worms 302 and 334 can be splined to the sleevesand assembled before the sleeve and gear are assembled as a unit. Eachworm 392, 364 is biased against its assoicated radial flange 2% or 309by a coil spring 306, 3% to afford a cushion or delay if the gears 274and 278 and 28% do not initially mesh when drive shaft 258 is shifted.

Best shown in FIGURE 4, each reel includes an associated linkage whichconstitutes a reel condition sensor and drive shaft reversing actuator.One is right-hand and the other is left-hand, otherwise they areidentical, so only the right-hand sensor-actuator 312 will be described.Portions of the sensor-actuators are deleted from FIG- URE 3 for claritybut details can be seen in FIGURES 4 and 5. The actuator 312 is U-shapedand is pivotally mounted on cars 314- and 315 mounted on the supportbracket plate 232 behind the assoicated ribbon spindle gear 278. One end3113 of the U-shaped member is formed as a long arm which projects to aposition inside the annular hub 317 in the rear of ribbon reel 282 (seeFIGURE 5) terminating in a right-angled curved finger 318. A spring 32f)connected between an ear 322 on arm 316 and an anchor lug 324 on bracket232 biases the actuator 312 clockwise (FIGURE 4) causing the curved fin'er 313 to engage the inside surface and edges of the reel hub 317. Ifink ribbon is present on the reel 282, the finger 318 will reach a limitposition determined by the ribbon. However, if the ribbon is exhaustedthe finger 318 moves out through a reel hub opening 326 under urging ofthe spring 320.

\Vhen the actuator 3E2 senses an exhausted reel and shifts to its fullclockwise position with finger 318 through a reel hub opening 326, a pin328 carried by a short arm 330 on the opposite end of the U-shapedactuator shifts up into engagement with the threads of worm 302. Sincethe ribbon feed drive shaft 2553 continues to rotate in steps as thecontrol circuits demand ribbon feed, the worm wheel 302 rotatesclockwise and the direction of feed of its threads against the axiallyimmovable pin 31% will shift the shaft to the right and cause meshing ofgears 274 and 278, after which shift, reel 282 becomes the takeup reel.The first turning movement of reel 232 as a take-up reel will causeretraction of the pin 238 of actuator 312 because the edges of the reelhub openings 326 and the winding ribbon will force the actuator 31?. toshift counterclockwise against the urging of its bias spring 320.

In the operation of the ink ribbon mechanism, a ribbon feed indexingstep will occur once for each two times the control circuit feeds asignal to the ribbon feed divide-bytwo register 58 (FIGURES 1 and 7). Ashas been described, once during a cycle of any of the four operativemodes, a signal pulse is fed to the ribbon feed divide-bytwo register 58which controls a ribbon feed one-shot (14 ms.) 6%) (see FIGURES l and 6)to momentarily energize the ribbon feed solenoid 64. In FIGURE 4,whenever ribbon feed solenoid 64 is momentarily energized, the plunger236 reciprocates forward against the bias of spring 238 and returns backunder spring force. Forward movement of plunger 236 indexes the ribbondrive shaft one step by means of linkage 242, 244, 248, pawl 252 andratchet wheel 256. A dctent 262 bears on the ratchet wheel teeth toassure single step indexing by the pawl 252. The ratchet 256 being fixedto shaft 258 causes shaft 258 to rotate clockwise one step to rotate twosmall gears 274 and 276 attached to ends of the shaft. One

or the other of gears 274 and 276 is meshed with an associated largegears 278 or 280 and rotates that gear. As illustrated in FIGURE 4,gears 274 and 278 are meshed, so gear 278, its spindle 270 and the inkribbon reel 232 carried by the spindle are rotated to Wind-up the inkribbon in indexed steps, the ink ribbon being removed from the otherreel 284. Thus, each time the solenoid 64 is energized the ink ribbon230 is advanced a slight distance until one of the two ink ribbon reels282 and 284- is almost emptied.

The sensing levers 316 and SM are employed to activate the ribbonreversing mechanism as seen in FIC- URES 35. In order to load (place areel on) the ink ribbon spindles 2'70 and 272, sensing levers 316 and316' must be moved downward, as viewed in FIGURE 4, by depressing manualoperating rods 340 and 342. This enables ink ribbon reels 282 and 284 tobe slipped onto spindle ends 236 and 288 with the curved fingers 318 and313' of sensing levers 316 and 316 fitting inside the hollow hub 317 ofeach ink ribbon reel (FIGURE 5). As the ink ribbon 2% completely unwindsfrom one ink ribbon reel, the curved finger end 318 or 318 of lever 316or 316' (until now, blocked by the ink ribbon wound on the reel) is nowunblocked and moves upward into an opening 326 on the inside rim of theink ribbon reel hub 317 (see FIGURE 5). This enables a shift of sensinglever 316 or 316 under bias of spring 320 until the pin 328 or 328 onshort arm 330 moves into engagement with the threads of worm gear 382 or304. If gear 3232 has its threads engaged by sensing lever shift pin328, clockwise rotation of the gear by shaft 258 will cause the shaftassembly to shift toward the right until gears 2'74 and 273 are in mesh(FIGURE 3) causing shaft 258 to drive spindle 270 and its ribbon reel282. Positive drive rotation of the ribbon reel will wind the ink ribbonon that reel and, through the sensing lever 316, will remove thereversing pin 328 from the threads of gear 302. Gears 274 and 278 willcontinue to rotate the reel 282 until reel 284 is empty, at which timeits sensing lever 316 will be raised to place its pin 328 into the wormthreads of gear 394 to shift the drive shaft assembly to the left,meshing gears 276 and 280, and place positive drive on reel 284 insteadof reel 282.

To make certain that shaft 258 remains in one or the other positionuntil a shift movement is desired, a spring loaded detent pin 344engages alternate ones of two side by side grooves 346 and 348 in thesleeve 296 of the lefhand small gear unit on the ribbon drive shaft 258.When the shaft assembly is shifted one way or the other to reverse theribbon feed, one of the grooves 346 or 348 moves laterally away from thedetent pin 344 which is then depressed by ridge 350 between the grooves,and the detent pin is then biased into the other groove to hold thedrive shaft assembly in such position until the ink ribbon is againreversed.

The invention may be embodied in other specific forms Without departingfrom the spirit or essential characteristics thereof. The presentembodiment is therefore to be considered in all respects as illustrativeand not restrictive, the scope of the invention being indicated by theappended claims rather than by the foregoing description, and allchanges which come within the meaning and range of equivalency of theclaims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States LettersPatent is:

1. In a high speed serial printer which undergoes a cycle of operationresponsive to reception of each of a plurality of different datacommunication signals, an ink ribbon feeding and reversing assemblycomprising: two reels; an ink ribbon passing between said two reels andadjacent the print positions of said printer; a reel feed mechanismadapted to alternatively be connected to one or the other of said tworeels; means responsive to ribbon condition on said reels to selectivelyconnect said feed mechanism to an appropriate one of said two reels; anelectronic power circuit connected to actuate said reel feed mechanismand step feed said ink ribbon assembly; an electronic control circuitresponsive to each cycle of printer operation to provide a ribboncontrol pulse; and a divide-by-two register receiving said ribboncontrol pulses and responsive to alternate control pulses to provide anactuation signal to said power circuit to trigger operation of saidelectronic power circuit.

2. In a high speed serial printer which undergoes a cycle of operationresponsive to reception of each of a plurality of dififerent datacommunication signals, an ink ribbon feeding and reversing assemblycomprising: two reels; an ink ribbon passing between said two reels andadjacent the print positions of said printer; reversible drive means,with automatic shifting means, to alternately drive either one of saidreels responsive automatically to substantially complete unwinding ofthe ribbon from the other one of said reels; an electronic ribbon powercircuit including a spring loaded solenoid connected to step feed saidreversible drive means; an electronic control circuit responsive to eachcycle of printer operation to provide a ribbon power circuit controlpulse; and a divideby-two register receiving said ribbon control pulsesand responsive to alternate control pulses to provide an actuationsignal to said ribbon power circuit to trigger operation of saidsolenoid to step feed said drive means.

References Cited by the Examiner UNITED STATES PATENTS 2,672,092 3/1954Beattie l0l-336 2,714,850 8/1955 Kistner 101-336 2,723,346 11/1955Magnuson 317-123 3,122,678 2/1964 Mariot 317-5 WILLIAM B. PENN, PrimaryExaminer.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3 ,232229 February 1 1966 Hilding A. Anderson It is hereby certified thaterror appears in the above numbered patent requiring correction and thatthe said Letters Patent should read as corrected below.

Column 4 line 58 for "alway" read always column 6 line 50 for "relay"read delay column 7 line 60 for "enregize" read energize column 9 line15 for "enregi zed" read energized column 11 lines 14 and 27 for"assoicated" each occurrence read associated line 53 for "238" read 328Signed and sealed this 10th day of January 1967.

( Attest:

ERNEST W. SWIDER Attesting Officer EDWARD J. BRENNF Commis ioner ofPatent

1. IN A HIGH SPEED SERIAL PRINTER WHICH UNDERGOES A CYCLE OF OPERATIONRESPONSIVE TO RECEPTION OF EACH OF A PLURALITY OF DIFFERENT DATACOMMUNICATION SIGNALS, AN INK RIBBON FEEDING AND REVERSING ASSEMBLYCOMPRISING: TWO REELS; AN INK RIBBON PASSING BETWEEN SAID TWO REELS ANDADJACENT THE PRINT POSITIONS OF SAID PRINTER; A REEL FEED MECHANISMADAPTED TO ALTERNATIVELY BE CONNECTED TO ONE OR THE OTHER OF SAID TWOREELS; MEANS RESPONSIVE TO RIBBON CONDITION ON SAID REELS TO SELECTIVELYCONNECT SAID FEED MECHANISM TO AN APPROPRIATE ONE OF SAID TWO REELS; ANELECTRONIC POWER CIRCUIT CONNECTED TO ACTUATE SAID REEL FEED MECHANISMAND STEP FEED SAID INK RIBBON ASSEMBLY; AN ELECTRONIC CONTROL CIRCUITRESPONSIVE TO EACH CYCLE OF PRINTER OPERATION TO PROVIDE A RIBBONCONTROL PULSE; AND A DIVIDE-BY-TWO REGISTER RECEIVING SAID RIBBONCONTROL PULSES AND RESPONSIVE TO ALTERNATE CONTROL PULSES TO PROVIDE ANACTUATION SIGNAL TO SAID POWER CIRCUIT TO TRIGGER OPERATION OF SAIDELECTRONIC POWER CIRCUIT.